Stored Program Controls — API Changelog

API Version 1.1.4 (April 11, 2026)

Cumulative changelog covering all changes since API 1.1.0.

Custom Function Block Nodes

• SpcNodeSchema: Declares node type structure (type ID, execution phase, ports, parameters, display requirement) for addon registration via SpcNodeRegistry.
• ISpcNodeFactory + NodeCompilationContext: Factories receive resolved signal addresses and parameter values at compile time.
• ISpcCompiledNode: Per-tick execution interface with access to the signal bus and world context.
• SpcNodeRegistry: Thread-safe static registry for addon node types, frozen after setup.

SpcNodeSchema Optional Metadata

• displayName: Human-readable name for the palette and tooltips (e.g. "Rotation Input"). Falls back to a formatted version of the typeId.
• shortLabel: Abbreviated label for the palette glyph (e.g. "RI"). Falls back to the first two characters of displayName.
• description: Tooltip description text (e.g. "Reads rotation data from a kinetic source"). Falls back to "N inputs, M outputs".
• labelPrefix: 1-3 character prefix for PLC-style editor labels. When set and the node has a channel parameter, the editor shows prefix + channel (e.g. "RI1", "RQ2") instead of the generic "B001" label. (Added in 1.1.4)

Signal System

• 6 signal types: Digital, Integer, Decimal, Text, Item, Item_ID.
• Full cross-type conversion (asDigital, asInteger, asDecimal, asText).
• SpcSignalAddress (nodeId + portId) for resolved signal bus addressing.
• Signal domains for port compatibility checking.
• readDecimalSignal() and double persistent slots (getDoubleSlot/setPendingDoubleSlot) for precise floating-point state.

Four-Phase Execution Model

• Input Read → Logic Evaluation → State Update → Output Apply.
• SpcExecutionPhase enum for declaring node execution order.

Persistent Node State

• Slot-based storage that survives across ticks and world saves.
• Integer slots (getSlot/setPendingSlot) and double slots (getDoubleSlot/setPendingDoubleSlot).

Custom Node Colors

• SpcNodeColors: Addons define custom ARGB colors (fill, stroke, text, labelText, activeFill).
• Convenience factories: SpcNodeColors.fromAccent(int), SpcNodeColors.of(int fill, int stroke).
• Nodes without custom colors fall back to the default brass palette.

Node Categories & Palette

• SpcNodeCategory: Custom palette groups with categoryId, displayName, sortOrder, and optional iconTexture.
• Addon nodes merged into the palette sorted by category sortOrder.

Programming Block Categories

• SpcProgramBlockCategory: Themed Programming Block variants with custom display names and visual styles.
• SpcProgramBlockStyle: Defines primaryTint, secondaryTint, emissiveTint. Includes fromAccent(int) factory.
• SpcProgramBlockRegistry: Thread-safe static registry, frozen after setup.

Multiblock Module API

• SpcModuleTypeRegistry: Register custom multiblock module types with optional I/O handlers.
• ISpcMultiblockModule: Interface for blocks to participate in LOGO multiblock BFS discovery.
• ISpcPhysicalIoHandler: Channel-based I/O handling for custom input/output modules.
• SpcMultiblockPosition: Position tracking within the multiblock structure (INPUT_ROW, OUTPUT_ROW, MIDDLE_ROW, POWER_ROW).
• SpcModuleType: Record declaring module identity, display name, position, and I/O flag.

Multiblock Connected Textures

• MultiblockPosition enum (with MB_POS block state property) included in the API jar. (Added in 1.1.3)
• 10 position values (TOP_FIRST, TOP_MID, TOP_LAST, CENTER_FIRST, CENTER_MID, CENTER_LAST, BOTTOM_FIRST, BOTTOM_MID, BOTTOM_LAST) plus NONE for unformed state.
• Addon blocks that register MB_POS in createBlockStateDefinition() automatically receive position-aware connected textures when the LOGO multiblock forms — borders are removed on internal seams, matching built-in blocks.
• Provide blockstate JSON variants for each (facing, mb_pos) combination and models inheriting from SPC's logo_mb_* parent templates.

Connected Display API

• ISpcConnectedDisplay: Interface for addon display blocks to participate in display-to-display connected textures. Return the display facing direction via getDisplayFacing(BlockState). SPC's built-in displays recognize addon blocks as valid texture neighbours. (Added in 1.1.2)

Diagnostics Panel API

• ISpcDiagnosticsProvider: Interface for addon block entities to contribute live diagnostic entries to the programming editor's Diagnostics Panel. (Added in 1.1.2)
• SpcDiagnosticEntry: Data record with label (String), value (String), and active (boolean). 2-arg constructor auto-detects active state. Entries appear in a dedicated "Addon" section of the diagnostics overlay.

Network Device API

• SpcNetworkRegistry: Register custom network device types.
• ISpcNetworkDevice, ISpcNetworkActivation, ISpcCableTraversable: Interfaces for custom network-connected blocks (buttons, levers, displays, etc.).

Runtime Events API

• SpcRuntimeEventRegistry: Register ISpcRuntimeEventListener implementations.
• Listeners receive callbacks for program lifecycle events (start, stop, error, tick).

Context Extension System

• SpcContextExtensionRegistry: Register ISpcExecutionContextExtension implementations for custom world interactions (e.g. Create rotational force, Mekanism gas levels).
• Extensions receive onTickStart(ServerLevel, BlockPos) each tick before node execution.
• Compiled nodes retrieve extensions via ISpcExecutionContext.getExtension(Class).

Bug Fixes (included in runtime jar)

• Addon blocks now recognized by multiblock validator. Previously, blocks implementing ISpcMultiblockModule were invisible to BFS structure discovery and type validation, causing "Missing Input Block" / "Missing Output Block" errors. (Fixed in 1.1.1)
• Port signal type mismatches no longer block simulation. If an addon changes a port's signal type between versions, existing saved programs reported a blocking error. Now reported as a warning with "Re-place the node to update" message. (Fixed in 1.1.4)

API Jar Contents

• 39+ classes across 12 packages under com.hypernova.spc.api.**
• MultiblockPosition class from com.hypernova.spc.multiblock.model (since 1.1.3)
• Separate compile-only jar: storedprogramcontrols-1.1.4-api.jar
• Runtime jar: storedprogramcontrols-0.2.0.jar (required in run/mods/)

Version History

• 1.1.0: Initial public API release (39 classes, 12 packages).
• 1.1.1: Fixed multiblock validator not recognizing ISpcMultiblockModule blocks.
• 1.1.2: Added ISpcConnectedDisplay, ISpcDiagnosticsProvider, SpcDiagnosticEntry.
• 1.1.3: Exposed MultiblockPosition (MB_POS) in API jar for connected textures.
• 1.1.4: Added SpcNodeSchema.labelPrefix; port signal type mismatch downgraded to warning.